Molecular typing of vibrio species isolated from seabass (Dicentrarchus labrax) and detection of antibiotic resistance

Objective: This research was carried out to identify Vibrio species isolated from sea bass by molecular methods and to determine their antibiotic resistance. Material and Methods: The research was performed with 100 sea bass samples taken from fish farms in the Aegean region between May-September 2021. After the isolates obtained from the samples were phenotypically and genotypically identified, antibiotic resistance was determined by disc diffusion method and antibiotic resistance genes were determined by multiplex PCR. Results: In this study, 46 (46%) Vibrio spp. isolates were obtained from 100 sea bass samples by conventional and biochemical methods. The obtained 46 isolates were confirmed to be Vibrio spp. by 16S rRNA PCR. From 46 isolates, 22 (47,8%) isolates were identified as V. alginolyticus, 13 (28,2%) isolates as V. harveyi, 3 (6,5%) isolates as V. parahaemolyticus, 1 (2%) isolate as V. vulnificus and 7 (15%) isolates as Vibrio spp. by Multiplex PCR. The highest resistance was found to ampicillin (84,8%) in the isolates in the antibiogram. All isolates were found to be susceptible to enrofloxacin and sulfamethoxazole-trimethoprim (100%). In isolates, the highest resistance gene was found to be trimethoprim resistance gene (63%), and the lowest resistance gene was found to be fluoroquinolone resistance gene (6,5%). Conclution: In this study, it was determined that Vibrio species have an important role as a primary agent in fish diseases, molecular methods give more reliable results in identification, and there is single and multiple antibiotic resistance among isolates.